What is Electromagnets: Definition and 87 Discussions

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in the hole, denoting the center of the coil. The magnetic field disappears when the current is turned off. The wire turns are often wound around a magnetic core made from a ferromagnetic or ferrimagnetic material such as iron; the magnetic core concentrates the magnetic flux and makes a more powerful magnet.
The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field.
Electromagnets are widely used as components of other electrical devices, such as motors, generators, electromechanical solenoids, relays, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment. Electromagnets are also employed in industry for picking up and moving heavy iron objects such as scrap iron and steel.

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  1. TheAmatuerHobbyist

    Electrical Electromagnetic confinement and Oscillators

    I am wondering if it is possible to use two electromagnets oscillating at about 1 ghz to suspend an amount of ferrofluid in an acrylic chamber. As I understand it, 1 ghz should be sufficient enough to get the ferrofluid away from each magnet, as after a quick google search, magnetic fields move...
  2. S

    How Do Electromagnets Repel Each Other in a Zero-Resistance Environment?

    Consider 2 similar solenoids/electromagnets with appropriate iron core with the following parameters: core Length (L), core Radius (R), electromagnet wire diameter (w), number of turns of wire/winding layer on the core (L/w), number of layers of winding (K), total number of turns ((L*K)/w)...
  3. B

    Superconductor Flux pinning/Meissner effect with electromagnets?

    I was reading about high temperature superconductors expelling magnetic fields (Meisner effect). I was curious if this only works with permanent magnets or is there similar effects with electromagnets. I assume since the magnetic waves would be similar there would be a similar reaction, but...
  4. N

    Right Hand Rule for Electromagnets

    Ok I’m trying to understand the right hand rule in relation to electromagnets. Since I’m a visual learner I made myself a little diagram. Is my little diagram correctly showing the flow of electrons relative to the magnetic poles? Also does the core and helix being slightly curved affect the...
  5. M

    Does Moving Coils in Electromagnets Create Current? Explained

    A small coil is moved forward (without turning) between the poles of the electromagnet. Does an electric current develop in the coil? Explain the answer
  6. Bernardtai

    Possible to connect two electromagnets perfectly together?

    Mission: create a pair of electromagnets which always connects (angel) perfectly together. Initially, I design with the following 3 ideas, could any design possible to achieve? 1) First idea is to separate 5 iron core, all close to the edge and connect to the battery source. this attempt is...
  7. M

    Looking for software to help me make electromagnets

    This is home project that I have wanted to do for years. I know I will have to build a lot of them to get what I need. I am hoping to find some software that will help me. I have looked and I can not find any electromagnets that will work. I will have to have odd shaped cores and they will need...
  8. N

    Help with electromagnets acting at a distance on an object

    Would the model in this diagram be able to keep the object stationary provided there is enough current? What equations would be used to calculate the forces acting on the object from the electromagnetic fields? -The object is equidistant from the electromagnets - The object is separated from the...
  9. S

    Electrical DIY project about electromagnets

    Hi there and thanks to anyone who responds. I am creating a DIY project that is getting a little complicated for my knowledge. Specifically, I need to have three electromagnets hooked up to a sequencer or a timer of some sort that supplies equal power to one electromagnet at a time, then...
  10. kolleamm

    Electromagnets, is thinner wire better? Quantity?

    Let's assume you have two electromagnets. One has wire with a 1mm diameter and the other has half that diameter 0.5mm. Assuming they both have the same mass of wire which would be stronger or better? Also if my goal was to attract an object, would it make more sense to have two thinner...
  11. Dante Meira

    Magnetic repulsion between a permanent magnet and an air coil

    I would like to receive some input about this "equation" formulated by me, a=f(i), regarding a system with a permanent magnet and an air core coil acting as an electromagnet, as described in the image: I understand that the acceleration provided to the toy car will be a function of the...
  12. C

    How can I make my homemade electromagnets repel each other?

    I have two homemade electromagnets and I need them to repel each other (essentially, be able to physically spin around). Each feels about as strong as a decent fridge magnet when connected, however when I put their opposite poles next to each other, they do not repel - they only feel like...
  13. Alex Schmitt

    How to make a short range, remote-controlled electromagnet?

    I am currently working on my high school's upcoming production of Beauty and the Beast. In the musical, there is a rose which loses petals at specific moments in the script that represent the castle's inhabitants slowly becoming less human. I figured that one of the best ways to do this remotely...
  14. J

    Magnetic Levitation (electromagnets?) for an 11th grader

    I don't know if this is the right place to put this, but I am very lost as of right now. I am doing my 11th grade physics project on magnetic levitation. From what I can understand, there are 2 "main" types of magnetic levitation, them being with superconductors and with electromagnets. For the...
  15. M

    Magnetic repulsion of solenoids

    I'm trying to understand the repulsive forces of solenoids. This is all paper as in I don't actually have them to test in real life. Take two solenoids that are equal to each other. Specifications: current is 10 amps Number of turns is 300 Iron rod is 12 inches/ 304.8mm, with a Radius of 2...
  16. R

    Why does the Japanese Maglev train use superconducting magnets

    My little home made air-core solenoid makes 1.5T, why is it that superconducting electromagnets often aren't stronger than one would expect. Take the japanese maglev train for example: http://www.supraconductivite.fr/en/index.php?p=applications-trains-maglev-more According to this article the...
  17. C

    Physic project -- DC motor with electromagnets

    1. The problem statement, all variables and given I do not have a clue where to get the information to built a DC motor with four electromagnets Homework EquationsThe Attempt at a Solution
  18. N

    Help in designing electromagnets

    Hi all, First post, be gentle... I'm trying to build a system based on the MIT Actuated Workbench. They used electromagnets with the following spec: 1.9cm (0.75”) diameter x 3.8cm (1.5”) length, wound with 32-gauge copper wire with a total length resistance of 120-122 ohms, with no metal...
  19. N

    Interesting experiment about the attraction between two magnets

    We know that the attractive force between the opposing poles of identical permanent magnets is a product of their field strength and that the total force diminishes as the distance between them increases. If we assumed the magnets to be point entities, the formulation is the same as that for...
  20. Asmaa Mohammad

    Using two electromagnets to study self-inductance

    Hi, I study physics and I know what the concept self-inductance means, and in one of my study books, a figure like this was used to explain the self inductance in a coil As shown in the figure, two electromagnets are connected together and the current is passing through them and would produce a...
  21. G

    Do electromagnets exhibit the same properties of a permanent

    I am just curious whether the formulas that apply to 'magnets', such as the formula for the magnetic field of a dipole (as brought up in my previous thread), apply to both electromagnets and permanent magnets, and other types? Is the magnetic fields exhibited by these different forms of...
  22. Hanarchist

    Creating a Maglev Track using Electromagnets?

    Hi All, I was wondering how I would go about creating a circular maglev track using electromagnets? The idea is to have more control over it and to eventually write a piece of code that would allow changes in the strength of the magnetic field potentially? I was just wondering how it would work...
  23. T

    How Can I Extend Battery Life in Classroom Electromagnet Experiments?

    I am currently working on and electromagnet experiment with my 8th grade students. I have been given an experiment where we build a basic electromagnet with an iron bolt, enameled wire and a 6V Alkaline Battery, (lantern battery). The goal is to test the strength by picking up BB's...
  24. S

    Strength of magnetic field on "eBay electromagnets"?

    How strong, approximately, is the magnetic field, on a powerful electromagnet, that you buy on eBay, that can lift, say, a 100 kg?
  25. DaveC426913

    B Electromagnets are a relativistic phenom?

    This is a new one one me: http://www.iflscience.com/physics/4-examples-relativity-everyday-life
  26. R

    Electromagnets and contactor relays

    I am supposed to make an electromagnet for a project. how will i know what gauge of wire to use and how many turns do i need so that my electromagnet will only get 100mA of current from a 24V dc source? Thank you!
  27. Shahryar

    Force between 2 electromagnets

    I am looking forward to know how to calculate the force between 2 electromagnets. what is the formula to find attraction and repulsion forces between them ? Thank you.
  28. S

    Net force between two Electromagnets considering Back EMF

    First this Q might be trivial thus apologies. Consider two bar electromagnets that can simulate bar magnets M1 and M2, placed end to end at distance D apart (North Pole of M1 facing South Pole of M2). Magnet M1 is 'fixed' to a base. Assuming both electromagnets have the Current I1 and Voltage...
  29. T

    Delay of free fall with electromagnets

    When you have a metallic ball hanging from a electromagnet and you disconnect the electromagnet, there is a delay between the moment you unplug the machine, and the ball starts falling. Why does this happen?
  30. Alex Mercer

    Correct electric charge/current flow & left/right hand rule?

    Hello there, people! I am quite new here; in fact, this is my first post. I am quite strange to this place. Feeling kinda welcome, though. Okay, so short to the point. I am an 8th grader, and my school just started teaching us about electricity. Well, the basics. I knew much about it, much...
  31. R

    Powering electromagnets with bicycle power

    Would it be possible to operate an electromagnet using the power produced by pedaling a bicycle? The electromagnet would need to be strong enough to lift up the training wheels of a bicycle.
  32. MagnetDude

    Engineering Textbook for electormechanical design reference

    I am working on a lot of things with electric motors, and many other electromechanical devices. Any textbook comes to mind?
  33. E

    Powering electromagnets question

    So I'm trying to build some electromagnets and i have some questions regarding how to power them. Imagine that i have a battery of 6 Volts and a coil with x gauge with y meters of wire that will equal 1 Ohm of resistance. So if i want to run it with 1 Amp of current i just put one 5 Ohm's...
  34. W

    Could i use electromagnets to increase the strength of a high speed

    Flywheel? I don't know much about magnets, but if i used magnets on the out side of a flywheel and the inside of the flywheel caseing which repel each other effectively crushing the flywheel to oppose centrifugal forces. Would this creat greater resistance on the rotation of the flywheel? Thanks
  35. P

    Dear EE'S I - sizing electromagnets

    Dear EE'S! I need help -- sizing electromagnets Is it possibile to built different electromagnet's sizes, that can produce the same magnetic field and forces(e.g attraction/repulsion)? If so how can I do that? By following this law: B = unl By controlling the number of turns or the amount of...
  36. S

    Can electromagnets create a variable magnetic spring?

    Hello, I'm Zach. Nice to meet you I have an idea I'm trying to work out in my head but don't have much experience with magnetics, especially electromagnetics so I'm helping someone could help me out a bit What my end goal is is a essentially a tube full of magnets that acts like a spring. If...
  37. D

    Switching polarity on electromagnets

    First off, hi, I'm new. Sorry if this is not the right board; I was unsure between Classical Physics, maybe Quantum since this involves fields, or Electrical Engineering. On to the question, say you have an electromagnet with an iron core. As I understand it, a magnetic field acts on a...
  38. T

    Help with electromagnets wiring method

    I am curious to know, why on a electromagnet that the wire coming in is on the opposite side to the wire leaving? Is it due to the way the current comes in and leaves, as in the anticlockwise field in the north so incoming and the outgoing is clockwise south. When I say a electromagnet I...
  39. I

    Controlling Strength of Electromagnets: Risks & Effects

    sorry if this thread is in the wrong place.. basically it's to do with electro magnets.. can you control the strength of them by something like a pedal? as in if you gradually push it the strength gradually increases? also would it be a health risk if you were right next to electromagnets...
  40. N

    Modelling static magnetic fields for electromagnets

    Hi guys, What I am trying to do is to create a mathematical model for the attraction forces between two or more electromagnets placed parallel to each other. (when the exitation currents are static) And for this i thought the best approach would be to have a model that can provide a 3D model...
  41. K

    Electromagnets and tuning forks

    I'm trying to get a steel tuning fork to remain vibrating at its designed frequency using an electromagnet. Is there any correlation between the strength of the electromagnet and frequency of the tuning fork, or is it more dependent upon the type of steel, size of the fork, distance, etc, etc..?
  42. D

    Superconductors, ElectroMagnets and MagLevs

    Guys I have a problem. Maybe, it's is a stupid one, but I really need help to comprehend something. I'm writing a report about applications of superconductivity. I chose the MagLev trains applications. Let's say, everything was fine until I read about the Meissner Effect. Now I have my mind...
  43. T

    Electromagnets and Conversation of Energy

    Running an electric current through a copper wire induces a magnetic field. Wrapping that wire around a ferromagnetic material amplifies its magnetic field (this is the basis on which electromagnets are designed*). This does not violate Newton's first law of thermodynamics because magnetic...
  44. T

    Can the Magnetoelectric Effect Propel Objects?

    The electrotoirdal effect was recently discovered. This article seems to me to describe it as the translation of a magnetic field without moving its origin: http://www.physorg.com/news/2011-09-physicists-magnetotoroidic-effect.html Is my interpretation correct? And could the magnetoelectric...
  45. K

    The work done by two electromagnets

    The "work" done by two electromagnets It has been said that magnets attract and repel by involving the use of electric fields. If so, how does the shape of the electric field change when an iron bar is magnetized? I would presume that the relative motion of the magnet as a whole is not what...
  46. K

    Electromagnets Repelling Metal

    I have a small physics book that states that if you run electricity throught a magnet it will repel metal. I just want to know if this is true.
  47. D

    Electromagnets and spinning objects

    Okay, so let's say there is an object with a shaft connected to it. The shaft rotationally spins the object. On the top and bottom of the object are N magnetic fields. Not touching the object or shaft are magnets attached to a solid surface with N fields. Those are within distance to act on...
  48. T

    Uncovering the Mysteries of Tesla's Coil for Electromagnets

    Linked below for exact specifications. I haven't heard of this one of Tesla's inventions used for anything, does anyone know if it works, surely it does if it was granted a patent? If so why and what is it used for or if not why not? Anyone? Thanks very much! Link...
  49. X

    Electromagnets and Conductors: The Effects on a Pendulum

    Question: Describe what will happen when a magnet suspended in the form of a pendulum is affected by an electrical conductor in close proximity. My working: Lenz's Law states that the emf induced in a conductor will oppose the emf of the change that produced it. Let's say I designed my...
  50. L

    How Would the World Function Without Electromagnetism?

    What do you think would the world be like without electromagnetism?